Gas chromatographic mini-columns packed with very fine liquid-modified particles of graphitized carbon black

The effect of decreasing the particle size of graphitized carbon black (GCB) from 60 to 20 μm on column efficiency has been investigated. The H̄min. value was found to decrease linearly as the mean particle diameter is deacreased. As a result, a plate height of about 0.06 mm, which corresponds to 17,000 plates per metre of column, has been achieved by using 20-25μm GCB particles. Unlike gas-liquid columns, the optimal mobile phase is practically unaffected by variations in the particle dimater of GCB. Very fine particles of carbon supporting a stationary phase have been evaluated in terms of selectivity, efficienty and column loadibility with varying amounts of liquid phase. For routine use in the analysis of high-boiling, polar compounds, a 21 cm × 0.5 mm I.D. glass column packed with GCB particles with a mean particle diameter of 29 μm, coated with a very thin film of stationary phase and fed with hydrogen as the carrier gas, was found to be the best arrangement in terms of analysis time, efficiency, column, loadability and pearmeability. Some analytical applications to steroids, oxygenated diterpenes, barbituates, nitro- and chlorophenols, free fatty acids up to C10 and glycols are reported. © 1978.